Airplane describing system



Dec. 30, 1941.- E. w. BRIXNER AIRPLAIE DESCRIBING SYSTEM 3 Sheets-Sheet l Filed June 4, 1938 Glass ATTORNIEY l VENT BY v %w mwa 4 ooo MM o PDS Dec. 30, 1941. FQW. BRIXNER AIRPLANE DESCRIBING SYSTEM Filed June 4, 1958 3 Sheets-Sheet 2 TILL S :o &83 65 F. W. BRIXNER AIRPLANE DESCRIBING SYSTEM Dec. 30, 1941.

Filed June 4, 1938 3 Sheets-Sheet 3 INVENTO i M TTORNIEY 4 I dom co 333 65 SEE :o P E:

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Patented 30, 1941 4 az azo marum: nascmmc szsrm rme-c w. me Gates, N. Yanni :nor to General Rallway sixnal Company, Rochester,

- Application June 4, 1938; Serial No. z,9c

' cam (c 177 333 The present invention relates' to a system for describing the character or airplanes, such as passenger or mail, and the route over 'which they fly as well as the ,elevation at which they' are instructed to fly as they enter an air port.

With the growth of airplanetrafllc and the advancement that has been made in blind flying, that is flying wholly by instruments in case of log, and tor other reasons; it is important to have airplanes which arrive at the-same air port to fly at definite altitudes during their wait i'or` permission to make a landing; For lnstance, ii there .are three airplanes arriving atthe same air port at substantlally the same time, it is important that these airplanes be instructed to enter such port at deflnite elevations, the flrst plane to make a landing being instructed to take the lower of three elevationa and the plane instruoted. to land last being instructed to take the highest elevation as it entersth' port. ;In practice it is found that the aii-plane dispatcher, the man who is in 'telephonic communication who is in communication with airplanes not so equipped by code ilashes oi' light ot various colors given in, diflerent combinations or order, must `be located so as to be able to view the entire surrounding sky. -For this reason he 'is prefer- 'ably located in a tower having-a glass dome root to give him the necessary visibllity of all in-com ing planes. In the more crowded air portsit is round tha an attendant known as a plane dispatcher" is kept busy by keeping his eyes on the field and by with .airplanes equipped with wireless telephones'and that inconsistent indications cannot be given, and.

so that an indication displayed by the movement of a key .on one panel may be extinguished by the movement oi' a key on the other panel, and

at the same time' leave the apparatusin such condition that the indication may again be displayed by the operation oi' the key on said one panel. Another object of the present invention is to so divide the work between the traflic man- -ager and the plane dispatcher, by the .provision of suitable apparatus, that each may give information to the otherwithoutthe use of a telephone or direct' conversation, and in a manner so that these informations cannot be inconsistent. Another object of .the present invention is 'to so divide the work between the traflic manager and the plane dispatcher that the traflic manager need not havea view oi' the flying field or air port, his information being entirely derived from a loud Speaker which announces all of the telephonic communications between the plane dispatcher and the pilots oi' the various planes in in at a lower aititude than any 'ot said other V planes. In other words. the entire work must oi necessity be divided between at least two, men. In order that each man may know what the other man is doing it is propoud,` in accordance with the present invention, to emplo'y a suitable iliuminated board which not only deflnes the plane by its character or route but also denes the aititude at which the plane is permitted to fly into and'over theair port; Thls"'board or' boards depending upon-whether the 'two men are in the same or different rooms, must' be visible and controllable by both men in a manner so addition to that derived from the indication board located in his omce which is in' part controlled by himself and in part controlled by the' plane dispatcher.

Other objects, purposes and characteristic !eatures of the present invention will be in part described as the speciflcation progresses and will in part be obvious from the accompanying drawings which form a part of this application.

In these-drawings Fig. 1 illustrates a side ele- 'vation of the plane dispatche'r's ofllce, which ofllce is provided with a glass dome giving the plane dispatcher an unobscured view of the s y and field 'of the entire air port and below which is shown in thetramc manager's room containing' the apparatus necessary tor the traflic manager to perform his duties in connection with the ar-rival of planes.-

Flg. 2 shows the various circuits and apparatus tor controlling the lamps oi' the "elevation" portion oi' the indicating boards located in the plane dispatcher's and the trafllc manager's oilices; and

Fig. 3 shows the circuits and -apparatus for controlling the indicators of the 'identiflcatlonfi portion ol' the plane dispatcher's board and the tramc manager's board.

Apparatus I Referring to Flg. the building illustrated mayior convenience be called the trafllc ofllce oi!` an air' port. As illustrated, this building includes a suitable tower. preier'ably round in connated TM. Directly sponding to the the boards by the lamps the corresponding column.

plane B 2 i struction and comprising a' glass deme 2, to render the entire landing field or air port as well as the sky above and surrounding it visible to the plane dispatcher located in this tower designated PDT. Directly below this plane dispatcher's tower has been illustrated a roon for housing the trafllc manager and his apparatu's which is known as the trafllc manager's oflice and desigbelow the room TM and possibly in the basement ot the building has-been shown a relay cabinet for housing the relays of the control system shown in Figs. 2 and 3 of the drawings.

Referring to the this tower is provided with a board PDB which is divided into upper one designated "elevation" part designated "indicationsJ' plane dispatc'her's tower pPDT, plane dispatcher's two parte, the and the lower although any desired type ot electrically operated indicators i may be used, thepresent invention for con-` venience illustrates lamps for identifying the planes and their elevation, and hereinafter the word lamp is to be understood as one form of indicator. As illustrated there are six vertical rows of lamps shown in the upper or "elevation" portion of the plane dispatcher's board PDB, each row including six lamps designated !0001, 2000, 3000, 4000, 5000 and 6000, respectively. Each of these lamps when energized indicates that the plane identified by that column has been instructed to fly at an elevation in feed correnumber identifying that lamp. In other words, ii the lamp 2000 ot column I is illuminated, as illustrated, this signifies that the plane identified by column I has been instructed to fly at an elevation of 2000 feet. The same thing is true ot the next five vertical columns of lamps. The ilrst two columns of lamps have been designated X and X'. These two columns of lamps are employed tor identifying the planes and the elevations at which they are instructed to fly which arrive over route X; The planes. separate' from their. elevation, are characterized or deilned in the indication" portion of For instance, the energized lamp A in column X signifles that a plane ol type A such as a limited passenger plane, a local passenger plane, or a mail plane. is arriving on route X and the illumination of lamp 2000 manifests that this plane instructed to arrive at an 'elevation of 2000 Ieet. In column X'- the lamps B* and 4000 have been illustrated illuminated. This means that there is also arriving a plane B on'route X and that this plane Bi has been instructed to .fly at an elevation of 4000 feet. Referring for a moment tothe maplocated on the desk in the traflic manager's oflice miniature airplanes laid Since plane A is ahead A has been instructed to than has plane B so that on the line of route X. of plane B the plane fly at a lower level the plane A may make a landing without passing through the elevation or zone occupied 'by This map also shows a route Y which is not at this time occupied by any' plane, and for like reasons-the lamps in columns Y and Y' on the plane dispatcher's board PDB: and the traflic manager's board TMB are not lighted;

Referring again to this map on the trafllc manager's desk the plane C arriving on 'route z is evidently a first class plane and should have preference over the planes A and B on route X. 'For this'reason the plane c: has been iden- A, B or C located in TM, these planes A and B are. 4 shown on. this map by has been cal and corresponding lamps on the two boards are preterably connected in series, so that the accidental breaking of a circuit or the burning out of one lamp will cause the other lamp to likewise be extinguished, so that these boards at all times display the same indications.

Referring again to the plane dispatcher s tower PDT, the plane dispatcher is preferably provided with a radio telephone Tel preferably located on his desk, on which desk are also mounted elevation keys K K K- K K K and a cancelling push button CPB. On the wall of the plane dispatcher's tower is preferably located a call lamp CL and a call bell CB. If this lamp CL or bell CB is rendered active the same may be rendered inactive by pressing the carcelling push button CPB. This lamp CL and bell CBis rendered active each an additional plane has been identified in the plane dispatcher's tower by the operation of a manually operable push button PB on the tramc manager's panel TMP located in the trafilc manager's ofllce TM, as more specifically describedjhereinafter.

In the trafllc manager's office TM is provided a desk containing a map of the surrounding 'country illustrating the various air routes terminating at the air port shown by a circle AP. As above mentioned the traffic 'manager's oflice is' provided with a loud speaker Ls illustrated on the wall in the tramc manager's ofllce TM, which loud speaker announces the conversations in both directionsbetween the plane dispatcher and the pilots of the various planes equipped with wireless telephony. When a plane approaches, which is not-equipped with a telephone, the plane dispatcher will report this fact to the traffic manager through the medium of this same telephone Tel and loud speaker LS. On the trafllc manager's desk is also located the traflic manager's panel TMP. This panel is divided into two parts, as illustrated, the upper part being provided with six rows of push buttons, there being six push buttons in each row correspon'ding to the lamps in the "elevation" portion of the boards PDB and TMB. These push buttons have been designated PB to P'B successively as shown for the push buttons in the third column and as designated in Fig. 2 of the drawings. Depressionof the push button. PB for the third column oi' push buttons will cause the lamp 6000 in column Y of each of the boards PDB and TMB to be illuminated, all in a manner more specitlcally described hereinafter in connection with Fig. 2 of the drawings. `The lower part of the traflic manager's panel ,TMP contains six rows of push buttons, there' being three push buttons in each row. The push buttons of the 'third column have been designated PB^, PB and PB. and these push buttons in Fig. 3 of the drawings.

are also illustrated The depression of r the push button PB for column 3, for instance,

will cause the lamp A in the column Y of each o! the boards PDB and'TMB to be illuminated.

Let us now briefly consider the arrival of a plane, at the airport and the manner in which time' that' v 68,240 this 'plane isinstructed to land without consider-- ing the detailed apparatus and circuits involved in giving this instruction. Let us assume that the t'i-ame manager is occupying his stool TMS and that the plane 'A on route X has been reported V to be located at a certain point on route X and approaching the air port. The traffic manager' u being aware of the fact-that the plane C on route z is a superior plane he will reserve the 1000 feet elevation for the plane C and accord-- ingly will depress the 'push 'button PB^ in the first column and slmultaneously therewith will depressthe push button 2000 in the first column.- This manipulation on the part of the tramc manager will light the lamps A and 2000 in column X on both of the panels PDB and TMB. The tramc manager being aware of the fact that the plane C is superior will substantia-lly simultaneously` also press the push button !000 and l B in the filth column, thereby illuminating the lamps !000 and C in column Z on the` boards :PDB and TMB. This manipulation on the part of the trafllc manager will also 'sound the call bell CB and illuminate the lamp CL in the plane K shown in Fig. is the key K shown on the 4 plane dispatcher's desk in Fig. 1 of the drawings. Likewise, the push buttons PB and PE? in Fig. 2 are the push buttons correspondingly deslgnated' in the third column on the` tramc manager's desk in Fig'. 1 of the drawings. left hand row of lamps !000, 2000, 3000, 4000,

5000 and 0000 of Flg. 2 arethe lamps correspondingly designated and shown in column Y on the plane dispatcher's board PDB in Fig. l, whereas relay cannot be energized unless all of the relays dispatcher's ofllce PDT. The plane dispatcher gb having been wamed that new indications have appear-ed on his board will look at his board and depress the cancel push button CPB ,so as to ex- 'tinguish the call light' CL and tender the call bell CB no longer audible. The plane dispatcher ao 4 key may control the stepping relays through the will then lock out over the field and even though he sees the plane A approaching on rute X he is aware of the `!act that the plane which will sooner or later approach on route z is the first structions to the plane 'A on route X to cruise over the field at an elevation of 2000 feet. The

plane dinpatcher will then keep a look-out for' i the arrival of plane C on route z As soon as i 'one to be' landed and accordingly he will give in- :5

this plane C on route Z arrives the plane dis- 40 patcher PDB will give instructions by telephone to the pilotet this plane informing him that he is to arrive at an elevation of 1000 feet and to make a landing upon reaching the field.` Assoon as the plane C which arrived' on route Z has made its landng the plane dispatcher will operate his key K to the lower position 'and back to the middle position. This will cause' the lamp I 000 in column Z to be extin'guished on both of the two boards PDB and TMB. Had it. not been the lowermost lamp in the elevatioi'portion of the column the next lower lamp would have been lighted. For reasons pointed out hereinafter the identification lamp C in column z will also be extinguished. The plane dispatcher, who may be occupying the stool PDS, will then instruct by wireless telephony the pilot of the plane A on route X to come down to a level oi !000 feet and. immediately upon 'giving such instruction he will operate his key K to the lower position and back to the middle position, this will cause the lamp 2000 in column Xl to be extinguished and thelamp |000 in-column X on boards PDB and TMB to be llluminated.

Control 'appratw I In Flg. 2 has been illustrated the control apparatus `i'ocontrollng the "elevation" portion of the 'boards PDB and TMB. For `converience only the control devicerelays and lamps for the column 2 havebeen illustrated. Likewlse, only the control circuits and apparatus for the lamps A, B and C in column Y 'have been 'shown in, !18.3 o! the drawings.

Referring to m. 2 o! the drawings the ka? buttons PB to PB inclusive. u 'parent that 'the energization of a relay V and cannot be picked up unless the relay VI is picked i up. These stepping relays may be initially controlled by the pushbuttons PB to PB inclusive,

and may thereafter be 'controlled through the medium of the plane dispatchera's key K which medium of the step control relays ED and EU and slow acting half-step relay VP. i The call relay R affords a stick feature, in that it may be picked up' by the momentary 'depression of any one of the push buttons PB to PB incluslve, andremains stuck up until the cancelling push button CPB on theplandispatcher's boardhas been depressed. This'call relay CR when energized illuminates the call lamp CL, and sounds the call bell CB, both located in the plane dispatcher's ofllce. 4

As heretofore pointed out none of the stepping relays V2 to VG may be picked up unless all of the stepping relays of lower order are energized. By examining'the pick-up circuit for, the stepping relay'vl it is apparent that this pick-up circuit can only be closed by one of the push It is thus apthe illumlnation of its associated lamps is only possible by the operation oi `a push button PB located in the traffic n'anager's ofllce, and. that the plane dispatcher cannot by, his keys K to K cause the'initial energization of a plane ele- 'vation indicating lamp !000 to 6000. ,The halfstep relay VP performs very ,much the same function as does a half-step relay in any stepplng relay bank, in that it transfers the pick-up and stick circuits from one to another pick-up or stick bus respectlvely. It will be noted that this relav VP is provided with a stick contact 3 and two control contacts 4 and 5, respectively. In

'order to simplify the clrcuit arrangementillustrated in the 'drawinga the complete circuits including a battery have not been illustrate'd and merely the terminals and oi a. suitabl battery or other source of current have -been shown to signiiy the and terminals of one or more batteries used in the system. since,

thestick buses 0 and 0 are both connected to the terminal o! the .battery with the step control relay ED in its retracted position it is' immaterial whether or not the contact l ofthe The i source.

' to a source of current. In other words. the

relay VP does not perform any particular function so long as the step control relays ED and EU remain deenergized, and we need not consider the rela'y VP in the discussion of the con-- trol of relays V by the push button PB -PB The stepcontrol relay ED signifles by its letter D that it is-employed for stepping the relays V* down to a lower order, and the letter U of, the reference character EU signifies that this i ,contact a of relay VS and the 'contact of push relay EU when energized causes the stepping r`elays V to step up to a higher order, that is, the letter D signifles down" and the letter, U signifles "upJ' r Let us now observe how' depression oi the push b'utton' PB will cause all of. the stepping .relays Vi' to VG- to be picked up and how this causes 'the two lamps 6000 only to be energized.

' Depression of the push buttonPB closes the pick-up circuit for the lower winding of the relay V from the terminal through the bus 'wire o, the contact of push button PB A the bus wire I2, the lower winding of the relay V to the other terminal of the same source.

This causes the relay VI -to assume its picked up position thereby closing its contacts s, !4, I! and IS With the contact |3 of stepping relay VI closed a. pick-up circuit for the relay VZ is closed from battery through bus wire !0, contact of pushbutton PB to wires I'I and [8, back ,contact s of relay VS', wire 20, back contact. 2! 'of relay VB, wire 22, front contact !3 The closu'e of its stick contact 40 closes a stick circuit for this relay VU which includes this stick contact 48, the front contact u of relay V* 'and the back contacts I and 30 of the reiays VP and ED in multiple. With the stepping re-- lays Vi now picked up a pick-up circuit is closed for the stepping relay VS through the front button PB. The picking up of this stepping relay VS opens its back contact BI and closes its front contacts 52, 53 and 64. The closure of its contact 54 closes a stick circuit including this stick contact il, the front con ct 49 of relay vs and the back contact :I of relay ED.

It may be pointed out that the picking up of each of relays V2 to VS, inclusive, completed a' stick circuit for its next preceding relay. These stick circuits include the lower windings of these relays and may be readily traced in the draw- -ings. Also, as these relays Vi, V2, VI, V4, VS

andVB are successively picked up the relay VP was 'successively picked up and dropped, one

of relay Vi, wires 23 and 24, winding of the' relay V2, to the other terminal of the same With the relay V2 picked up its contacts 25, 26, 21, 28 and 29 are closed. The closure of contact 26 of relay V2 closes a stick circuit for the lower winding of the relay VI. Also, the closure of its stick contact 28 closes a stick circuit for. the relay V2 including this stick contact 28, the front contact !5 of relay' Vi and' the back contact 3! ofthe relay ED.

With the stepping relay V2 now energimd a pick-up circuit is closed for the lower winding of the stepping relay V3, which circuit includes the contact of the push button PB the back contact 35 of the relay V4 and the front 'contact 25 of the relay V2. The closure of this circuit picks up` the relay V3 thus resulting in closure of its front contacts 2l, 36, 31, 38 and' 35. The closure of its stick contacts& closes its stick circuit including this contact, the front contact 29 of relayV2 and the back contact 4 or 30 of the relay VP or ED, respectively. Also,

' with this relay Vl picked upa pick-up circuit is closed for the relay Vl which includes a con-.

tact of the "push button- PB, the back contact !9 'of'relay VS, and the front contact 2| of relay 'Vt With the relay Vl picked up in response to the closure of this pick-up circuit, it closes the front contacts 35, ll, 42, 43 and Il of this relay vl, and in turn closes the stick circuit for this 'elay VI including 'its stick contact 43,

. the front contact 39 of relay V: and the back contact ,ll of relay ED. With the stepping relay vl' energized a pick-up circuit is closed for the stepping relay VB which includes a contact of the push button PB, and the front contact 35 of 'relay Vl. Picking up of the relay V5 closes its front contacts e, u, 4 1, 40 and 49.

even stepping relay ispicked up. The depression of the push button PB also closes an enerv gizing circuit for the 'call relay CR readily traced in the drawing, which relay CR is then stuck up through its stick contact 68. The successive picking up of these stepping relays through the medium of contacts 50. 55, 56, 51,

58 and 59 causes successiveillumination of the lamps |000, 2000, 3000, 4000, 5000 and 6000, in column Y? in the order given, only one of these pairs ;of lamps being energized at one time, and the lamps 6000 only remaining energized. The

traflic manger having once depressed the push' button PB cannot thereafter change his indi- 'cation' to one signifying 'a lower trailic level.

Had the trafiic manager depressed the push` button PB he could thereafter have changed this indication to one signifying higher level, this being accomplished, for instance, by depression of the push button PB all as is obvious from the circuits illustrated in Fig. 2 of the drawingsand described above.

Let us now assume that the lamps 6000 in column Y on both of the boards PDB and TBB V are iliuminated and that the plane dispatcher desires tdhave the plane identified by the lampa in column Y to fly at an elevationof 5000 f` t. The plane disp atcher will first inform the p of this plane by telephone ethat he is to fly at an elevation of' 5000 feet. He will then operate his key K (see Figs. 1 and 2) to its lower posi'- tion, thereby closing an energizing circuit for the relay ED. Since with the relay Vi picked up the. relay VP is deenergized we must bear in mind that the contacts 4 and 5 of this relayVP assume their lower position. The picking up of the relay ED will open its back contacts 30, s, SI 'and 'IL' The opening of back contact 'll will open the stick circuit for the lower winding of the relay VS, the opening of the contact !I will open the stick circuit for the upper-winding of the relay VB, as a result of which the relay VO will assume its retracted position, because its 69,240 e 4 e before contact I was pick-up circuit has been opened by the release oi the push button PB' in response to the illuini- Let us now assume that the plane dispat her de-- sii-ed to have the plane under'consideratlon fly at an elevation of 4000 feet instead of 5000 feet. He will so inform the pilot by telephone and upon completion of the instructions he will again depress his key K resulting in the picking up oi' the "down" relay ED. Since the relay VP is now energized the stick' circuit tor the stepping relay e V! is dependent for its energization on a'closed,

back contact 30 of relay ED, the back contact 4 ot the relay VP now being open. Picking uqi the relay ED will thereiore break the stick c cuit i'or the upper winding of the relay Vi, and. since the stick circuit tor the lower winding oi relay VI is broken at the iront contact z of the relay VI and the pick-up circuit tor the lower windlns of the relay VI is open atcthe back contact I oi the relay VP, thisstepping relay VI will now assume its ret-"acted position, thereby extinguishing its lamp 5000 in the column Y* oi boards PDB and TMB and instead illumin'atins the lamp 4000 in this same column. In a similar' manner the relays maybe dropped irom any particular 'order to the next lower order by momenpicked up in the pick-up circuit oi 'relay VO. It is thus seen that the plane dispatcher cannot light a lamp in a dark column of the elevation portion of the board, but can merely change the indication from one elevation to another, and that'for each momentary depression of the key K the next lower lamp for that column is lighted and that for each momentary liiting of the key the next higher-lamp of that column is lighted. Also, if all the lamps of a column have 'once been extingulshed, by operation of push button K to deenergi'ze relay Vi by -the' plane dispatcher, he cannot restare an indicatlon in that column because there is no pick-up circuit ior the relay-Vl` which does not include a push button contact located on the traillc manager's panel TMP.

Control apparatus for the plane identify'ina lamps l As heretofore pointed out the depression of any one oi the push buttons PB^, PB and PB illustarily 'Operating the key K to its lower position V and returning it to its intermediateposition;

Let us now observe how the plane dispatcher may change an indication identifying a particular elvationa plane may fly to a lamp identii'ying a hlgher-xelevation. This is done by momentarily Operating the key K to its raised position and then retuming it to its intermediate position. With the lamp 4000 in column Y* still illuminated, that is, with the relays VlV2, V: and V4 all energized and the relays VI and VI deenerglzed we will also note that the relay VP is deenergized under this condition. The movement oi' the key K to its raised positionwill cause the "up" relay EU to pick up. Since the relays VP and Vi are both deenergized and the relay EU is now` energized, a pick-up circuit tor the relay Vi is closed which may be traced as follows: starting i'rom the terminal of the battery, iront contact 'II of relay EU, back contact I oi' relay VP, back contact Il oi relay VB, front contact Il oi relay V4, through the lowerwinding oi the relay VI to the other terminal (-)Z.`The closure oi this circuit will cause the relay VS to pick up thereby closlng its stick circuit including its stick contact 40, frontcontact 44 of relay V4, and the back contacts 3040! the relay ED and 4 oi relay VP in multiple. The picking up of this relay VI will cause the' relay VP to be picked up as soon as the relay EU is deenergized in response to return oi the key K toits intermediate position. This picklng up oi the relay VP will; however, not have any eflect on'the stepping relays V, because both back contacts 30 and 3! of relay ED maintain the various stick circuits for the upper winding oi the relays VI to' Vil, inclusive, closed. Also the picking up oi relay VP will notresult in the energlzation of relay VS, becausecontact 'I: dropped trated on the traflic manager's panel in room TM i will cause the corresponding lamps A, B or C for the column Y* to be illuminated.- These push buttons PB'E PB and PB are also shown in Fle. 3 of the drawings, as are also the lamps A, B and C located in column Y* of the indicating boards PDB and TMB located in the plane dis-` patcher's room and the trafllc manager's room, respectively. Refer'ring to Fig. 3, it will be noted that the lamps-A on the two boards will be enerv gized when the relay AR alone is energized. that the lamps B will be energized when the relay BR alone is energized, and that the lamps C will be energized when the relays AR and BR are both energized. Al'so, itis readily apparent from the circuit shown in Fig. 3 that depression of the push button PB^ closes a pick-up circuit for relay AR, that the' depression o'f the push button PB will result in closing a pick-up circuit tor the relay BR,'and that depression of the push button PB will result in closure of the pick-up circuits for both-of the relays AR and BR. Also, lt is apparent from these circuits for relays 'AR and BR that stick circuits for these relays will be closed as soon as these relays' pick up, providing that the stepping relay VI for the corresponding column Y* is in its attracted condition. This is true because the stick circuit for the relay BR, for instance, includes the front contact 34 oi the stepping relay V| (see Figs. 2 and 3) and a includes the stick contact" of the relay BR (see Figs. 2 and 3'). It is thus seen that the depression of the push buttons' PB PB or PB will cause the temporary illumination of the lamps A, B or C for the column Y* of the indicating boards, and that the particular indication will be retained only if the stepping relay VI i energizer. It should be remembered that relay VI will be. up i! any one of the six elevation indicating lamps tor that column is illuminated.` In other wo ds, if the trafllc manager depressed any one oi the push buttons PB to UB of column Y simultaneously with the depression oipush button PB^ he will cause the A lamp in column Y* to be permanently energized with the temporary energization of one of the lamps 1000-6000 in this same column; The energization of the elcvation lamps IOM-0000 is said to be temporary because theplane dispatcher may switch from one lamp to another, and the energization of the plane identifying lamp issaid to be permanent because the plane dispatcher can only cancel it.

'76 It is,of course, understood that the circuit dia i or indicators.

;except as demanded by 6. grams and associated apparatus shown in Figs. 2 and 3 is duplicated for each ot the six columns on the indication boards. Also. what has been said about the control of lamp !i is true of lamps B and C. J

Although the indication boards have been illustrated as being mounted on the wall and away from the control panels it is to be understood that the plane dispatcher's control panel may be directly associated with his indicating board so that each of his control keys K are located directly below the corresponding column of lamps Similarly, the indication board TMB located` in the trafllc manager' ofilce may be directly associated so that each ot his rows of push buttons PB is located directly under the column oi lamps or indicators for that column on his board TMB. Also, it is to be understood that in those cases where both the trafllcmanager and the plane dispatcher are located in the same omce a single indication board mountedso as to be viewable by both of these men may sufllce, and that in this case each of these men will have readily accessible. his own particular control panel sothat,

both of these control panels may be used to control a single indication board; Also, it is to be understood that-the plane dispatcher will be provided with suitable signal lamps to-transmit inormation to. pilots flying planes which are not equipped with radio apparatus, and in this case with his control panel TMP,

a,2es,a4o

push button contact; means controlled by said two contacts. respectively, to pick up a relay oi' the next higher order than a relay already picked up. and to drop the relay ot highest order then picked -up, depending upon-which ot said two contacts is closed; and an energizins circuit for each lamp closed only i! the relay associated with that lamp is in its pickea up position and all the relays of higher order are fin 'their retracted position.

3. In airplane describers, in combination, a

manager's location, a dispatcher's' location, a`

series of normally inactive indicators at the dispatcher's location, control means at the manager's location selectively operable to make any one of said indicators active,` control means at the dispatcher's location operative, only if one o! the indicators be active, to make any other the'plane dispatcher will speak into his telephone instrument the instructions transmitted by light signals to the unequipped plane, so as to inform the traffic manager through the' medium of the same loud Speaker LS the instructions given to such an unequipped plane. the various panels, boards and relay cabinet are connected by conduits to facilitate wiring.

The applicant has thus disclosed a specific embodiment of apparatus embodying'the invention as illustrative'of apparatus which may be em ployed to carry out his invention, and it is to be understood that this disclosure isan exempliflcation of apparatus that may be employed to carry out this invention and is not to be taken in a limiting sense, in that numerous modifications, adaptations and additions may be made without departing from the spirit or scope of this invention for one of said plane identifying indicators, and

a stick circuit for "said other stick relay including a contact which is open only it all of the stick relays of said series'are in their retracted condition.

2. In combination; an indicating board: a series of lamps, varying from lowest to highest order on said board; two control panele:: a series of push button contacts, one for each lamp, on one panel and two contacts on the other of said the scope of the following As shown in Fig. 1 i

of the indicators active whilemakingthe active indicator inactive.

4. In airplane describrs, in combination, a manager's location, a dispatcher's location, a series of normally inactive indicators at the dispatcher's location, control means at the .manager's location selectively operable to make any one ot said indicators active, control means at the dispatcher's location operative, only if one of the indicators be active, to make any other o! the indicators active while making the active indicator inactive or for making all of the indicators inactive.

5. In airplane describers, in combination, a manager's location, a dispatcher's location, a

series ot normally inactive indicators at the dispatcher's location, control means at the manager's location selectively operable to make any one of said indicators active, control means at the dispatcher's location operative, only it one of the indicators be active, to make any other oi the indicators active while making the active -indicator inactive, or tor making all of the indicators' inactive, the control means at the manager's location being ineflective to make anactive paneis; a series of relays with one relay for each of said lamps, each relay except that of the lowest order having a pick-up circuit including a front contact of the relay, of the next lower order, and,- in multiple its' push button contact and those of all the relays of higher order, pick-up circuit for the first relay including Its indicator inactive without making an indicator active.

6. In airplane describers, in combination, a manager's location, a dispatcher's location, ,a series of normally inactive indicators at the dis'- patcher's location, control means at the manager's location selectively operable to make any one of said indicators active, control means at the dispatcher's location operative, only it one of the indicators be active, to make any other of the indicators active while making the active inactive indicator inactive, a like series of normally in-f active indicators including an indicator corresponding with each of the indicators at the .dispatcher's location at the manager's location, and circuit means connecting the corresponding indicators at the two locations in series so as to assure, at all times, the presence oi identical indication aspects at the two locations.

7. In airplane describers, in cmbination, a manager's location, a dispatcher's location, a

series ot normally inactive indicators at the dispatcher's location, control means at the manager's location selectively operable to make any one of'said indicators active, control means at the dispatcher's location operative, only i! one or the indicators be active, to make any other of the indicators active while making the active 'indicator inactive. or for making all otthe indicators inactive, the control means at the manager's location being ineflective to make the indicators all inactive after having made an indi- 4 assure, at all times, v indication aspects at the two locations.

aeeae o cator active, a like series of normally inactive indicators including an indicator corresponding with each 'of the indicators at the dispatcher's location located at the manager's location, and circuit means connecting the correspondng in dicators at the two locations in series so as to the presence of identical 8. In airplane describers, in combination, a manager's location, a dispatcher's location, a

'series of normally inactive indicators at the dispatcher's location, control means at the manager's location selectively operable to make any one oi said indicators active, control means at the dispatcher's location operative, only if one of the indicators be active, to make any other of the indicators active while making the active indicator inactive, or for making all of the indicators inactive, another normally inactive indicator at the dispatcher's location, control' means atthe manager's location operable to make said other indicator active, the control means at the dispatcher's location being ineflective to control said 'other indicator except to 'make 'it inactive upon making all'of said series of indicators Inactive.

9. In airplane describer systems, in combination, two Stations, a series of normally inactive indicators at one station, each indicator, when active, denoting a particular, and different, elevatlon, control means, at the otherstation electively operable to make any one of the indicators active, control means at said one station effective, only while anindicator is active, to make the then active indicator inactiv and to make a difierent indicator, corresponding to either a higher or a lower elevation, active. V

-10, In airplane describer systems, in` combination, two Stations, a series'of normally inactive indicators at one station, each indicator, when active, denoting a particular, and diflerent, elvationpcontrol means at the other station selectively operable; to make any one of the ina dicators active, control-means at said one station efiective, only while an indicator is active,

i to make the then active indicator inactive and means at said other station for making said other indicator active, said control means atsaid one station Operating, upon making Inactive the indicator of said series denoting the' lowest elevation, to make said-other indicator inactive, a like seriestof lndicators and a like said other indicator at ,said other station, and means causing the indicators at the two Stations to always display the identical indications.

12. In combination. an indicating board, .a se- 'ries of indicating lamps on said boardand arranged in order from first'to last, a stick relay for each lamp, a manually controllable contacttor each relay, a pick-up circuit for each relay, except the first,` including a front contact of the next preceding relay and, in multiple. its own manuallycontrollable contact and those of the relays beyond it. the pick-up circuit of the first relay ,including 'its own manuallycontrollabe contact, a 'stick circuit for each relay including' other manually controllable contacts. and a circuit tor each lamp including a front contact of -its relay and a back contact of each relay beyond whereby only the lamp associated with the relay of the highest order picked up, is energized.

i 13.' In combination, an indicating board, a series 'oi indicating lamps on said board and arranged in order from first to last, a stick relay for each lamp, a manually controllable contact for each relay, a pick-up circuit for each relay, except the first, including a front contact of the next preceding relay and in multiple, its own manually controllable contact and those of the relays beyond it, the pick-up circuit of the first relay including its own manually controllable contact, a stick circuit for. each relay including other manually controllable contacts, a circuit for each lamp including a front contact' oi *its 40 relay and a' back contact of each relay beyond,

whereby onlythe lanp associated with the relay of the highest order picked up.- isenergized, and a manually controllable means eflective when operat'ed. and any one e! the relays is in at'- tracted position, toenergize the relay o! the next make' a different indicator, co'responding to ei- 4 ther a higher or'a lower elevation, active, an-

I other normally Inactive indicator at; said one station denoting plane characteristics when active, control means at said other station for making said other indicator active, said. control means at said one station operating, upon mak-' ing inactive the indicator of said series denoting the lowest elevation, to make saidother indicator inactive. r

'11. In airplane describer systems,` in combinaition, 'two Stations, a series of normally inactive indicatorsatone station, each indicator, when active, denoting a particular, and diflerent, elevation, control means at the other station selec tively operable to make any .one of the' indicas'o for each lamp,

higher order. V 4 14. In combination, an indicating board, a se-, ries of indicating lamps on said board and arranged in order !rom first to 1ast,-a stick relay a manually controllable contact fon each relay, a pick-up circuitfor each relay, except the first, including a front contact of the L next preceding relay and,'in niultiple; its own manually controllable contact and those of the relays beyond it, the* pick-up circuit of the first relay including its own manually controllable contact, a stick ci'rcuit tor each relay including other manually controllable contacts, a circuit tor each lamp including a frontacontact o! its relay and a back contact oi each relay beyond tors active, 'control means at said one station effective, only while an indicato" is active, to make the then active indicatoinactive and make 'wherebyonly the 'leninassociated` with the 'relay oi the highest order picked up. energized, and a .manually controllable means efl'ective when operated in one maune::. and any one oi 35 the elays is in attracted position, to energize the a diflerent indicator, corresponding to either a' higher or a lower elevation, active, another normally inactive indicator at said one station denoting plane characteristics' when active. control relay ot the next higher order", and when operated in a diflerent manner to deenergize the aa lay of the highest order then'energized. FREDEBICK W. BRIXNER, 

